Transitioning off Asacol & Librax to Sulfasalazine & Bentyl - Problems

After almost two years of the best health I have enjoyed in my 13 with IBD, GAD, and UC, my insurance is requiring me to change from Asacol and Librax. My GI has put me on Sulfasalazine 500 mg, now six daily, and is starting Bentyl tomorrow.

Since starting Sulfasalazine a week ago I have had nausea, lots of stomach pain, gas, urgency, increased bowel movements, bowel changes, dizziness, and general jumpiness and anxiety (GAD has been controlled and out of the way for years--until now). Anyone else familiar with changing these meds?

I don't know if the symptoms are from the Sulfasalazine or the removal of Librax, but I feel like in a week's time I have gone from perfect health to terrible again. Just had a colonoscopy (number 5!) last week, and all is well with the bowel.

Not sure whether to call my Psychiatrist for an adjustment of my GAD med now that the Librax is gone (or if there is a withdrawal period), insist the Sulfasalazine be changed, or sit and wait it out! I have a hospital internship starting next week which will require full functionality which makes me less apt to just sit and wait with this one.

Your suggestions and experiences welcomed!